A kind of zero cement solid waste heat-resistant concrete based on retired wind power blade glass fiber reinforcement and its preparation method

Abstract

The application discloses a kind of based on retired wind power blade glass fiber reinforced alkali-activated zero cement solid waste heat-resistant concrete and preparation method thereof.The concrete includes slag powder, fly ash, carbonized steel slag powder, natural coarse aggregate, carbonized steel slag coarse aggregate, river sand, carbonized steel slag fine aggregate, water, alkali-activator, modified retired wind power blade glass fiber, water reducing agent and retarder;The modified retired wind power blade glass fiber is obtained by cutting, chopping, milling and screening the waste wind power blade in sequence, and then modified by NaOH solution and aminopropyl triethoxysilane solution.The application uses slag powder, fly ash, full particle size gradation carbonized steel slag and modified retired wind power blade glass fiber as raw materials, which can realize high-value recycling of solid waste, significantly reduce the cost of material preparation and reduce environmental pollution.The carbonized steel slag can enhance the radiation protection effect of the concrete through electric conduction loss and interface reflection after being mixed.

Description

Technical Field

[0001] This invention belongs to the field of building heat-resistant materials technology, specifically relating to an alkali-activated zero-cement solid waste heat-resistant concrete based on glass fiber reinforcement of retired wind turbine blades and its preparation method. Background Technology

[0002] Against the backdrop of rapid development in the metallurgical industry, the output of various industrial tailings, such as steel slag, continues to rise. Large-scale stockpiling not only wastes land resources but also causes environmental pollution and safety hazards. Simultaneously, the over-exploitation of natural sand and gravel resources exacerbates ecological pressure, making it imperative for the building materials sector to seek sustainable development paths. Steel slag and blast furnace slag undergo high-temperature quenching above 1500℃ during the smelting process, resulting in a dense mineral structure and strong chemical stability, endowing tailings-based aggregates with excellent high-temperature resistance. Processing them into coarse and fine aggregates to prepare heat-resistant concrete not only enables the large-scale disposal of solid waste from the metallurgical industry but also significantly improves the fire resistance, heat insulation, wear resistance, and impact resistance of concrete. Furthermore, the demand for radiation protection is increasingly urgent in electromagnetically sensitive buildings and other scenarios. Ordinary concrete has limited shielding effectiveness and is insufficient to resist gamma rays, neutron rays, and electromagnetic waves, easily leading to equipment malfunctions and harm to human health. Steel slag, as an industrial solid waste, is rich in heavy elements such as Fe and Ca. After carbonization, it forms a dense structure that can attenuate photon radiation through the photoelectric effect and Compton scattering. Simultaneously, its ferromagnetic minerals can enhance electromagnetic wave loss. Decommissioned wind turbine blades contain conductive and magnetic components such as carbon fibers, possessing both high specific strength and electromagnetic shielding potential. When synergistically incorporated with steel slag into concrete, a dual protection system of "heavy element attenuation + conductive network loss" can be constructed. This combination not only significantly improves the shielding effectiveness of concrete against gamma rays and electromagnetic waves but also achieves the resource utilization of solid waste. While balancing protective performance and environmental benefits, it reduces the cost of radiation protection projects, demonstrating significant engineering practical value and ecological significance.

[0003] However, using steel slag as aggregate to prepare cement concrete poses a risk of alkali-aggregate reaction. On the other hand, free calcium oxide and magnesium oxide in steel slag react with water to form calcium hydroxide and magnesium hydroxide. Both of these problems can lead to delayed cracking of concrete components, seriously compromising structural safety.

[0004] Meanwhile, existing heat-resistant concrete technologies have numerous problems in their preparation and use. Patent application CN115368037A discloses a heat-resistant concrete cementitious material and its preparation method and application. This patent document points out a method for preparing heat-resistant concrete materials with a temperature range of 200-500℃ using slag-based materials, gypsum, and sulfoaluminate cement clinker. However, the high cement content leads to large carbon emissions, contradicting the trend of low-carbon and environmentally friendly development. Patent CN109455988A discloses a method for preparing a 400℃ heat-resistant cementitious material. This method uses blast furnace slag as the main cementitious material and incorporates 10-20% silicate cement as an alkali activator. However, the activating activity of the slag powder is low, resulting in low strength. Patent CN113372063A describes a heat-resistant concrete prepared using materials such as silicate cement, basalt crushed stone, sand, admixtures, and modified copper-plated ceramic fibers. However, the ceramic fibers need to be sintered at 700-800℃ for 10-12 hours, which has drawbacks such as excessive energy consumption and unclear radiation protection capabilities. Summary of the Invention

[0005] To address the problems existing in the aforementioned background technology, this invention provides an alkali-activated zero-cement solid waste heat-resistant concrete based on glass fiber reinforcement from decommissioned wind turbine blades and its preparation method. This heat-resistant concrete uses solid waste such as slag powder, fly ash, steel slag powder, and glass fiber from decommissioned wind turbine blades as raw materials, achieving efficient utilization of solid waste resources. By using auxiliary cementitious materials such as slag powder, fly ash, and carbonized steel slag powder to replace cement, and constructing an alkali-activated cementitious system with an alkali activator, the performance of the cementitious materials is improved. Furthermore, the addition of coarse and fine aggregates of carbonized steel slag to the concrete, and the use of glass fiber from decommissioned wind turbine blades as reinforcing fibers, enhances the fire resistance and radiation protection performance of the concrete structure. The product obtained by this invention possesses excellent workability, can withstand high-temperature environments of 400~800℃, and has multiple advantages such as radiation protection, high strength, low shrinkage, and crack resistance. It also exhibits outstanding low-carbon and environmentally friendly properties, significantly reducing environmental pollution from solid waste disposal. It is suitable for diverse applications such as high-temperature scenarios in the metallurgical industry and radiation protection engineering, combining ecological benefits with practical engineering value.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0007] An alkali-activated zero-cement solid waste heat-resistant concrete based on glass fiber reinforced decommissioned wind turbine blades comprises the following components in parts by weight:

[0008] 63-80 parts of slag powder

[0009] 25-35 parts fly ash

[0010] 5-20 parts of carbide steel slag powder

[0011] 92-136 parts natural coarse aggregate,

[0012] 138-204 parts of coarse aggregate made from carbide steel slag.

[0013] River sand 96-135 parts,

[0014] 64-90 parts of fine aggregate from carbide steel slag.

[0015] 45-60 parts water

[0016] 5-10 parts of alkali activator

[0017] Modified decommissioned wind turbine blades, 1-3 parts fiberglass,

[0018] Water-reducing agent 0.5-3 parts,

[0019] 0.5-3 parts of retarder;

[0020] The modified decommissioned wind turbine blade fiber is obtained by cutting, crushing, milling, and screening decommissioned wind turbine blades in sequence, and then modifying them with NaOH solution and aminopropyltriethoxysilane solution, with a length of 6~12mm.

[0021] The steel slag powder, coarse aggregate, and fine aggregate are all made from raw steel slag ore, which is obtained through crushing, screening, and carbonization. The raw steel slag ore originates from a metallurgical plant in Shanghai. The derived steel slag coarse aggregate (4.75~20mm), fine aggregate (0.075~4.75mm), and steel slag powder (<0.075mm) are all prepared through the following specific process:

[0022] (1) Using steel slag ore as raw material, the ore is crushed by a jaw crusher and then graded and screened. While removing impurities, the undersize material with a particle size of less than 4.75 mm is retained as raw material for fine aggregate of carbide steel slag and powder of carbide steel slag.

[0023] (2) In step (1), steel slag coarse aggregate with a sieve residue size of 4.75~20mm is obtained by grading and screening. It is then subjected to high-pressure water washing (to remove dust), pre-wetting mixing and homogenization, and carbonization treatment. Finally, carbonization product debris is removed by secondary screening to obtain standardized carbonized steel slag coarse aggregate with a specific surface area of ​​150~750 m² / kg and a density of 3.1~3.8 g / cm³.

[0024] In step (2), the moisture content of the steel slag coarse aggregate is controlled to be 10-15% through pre-wetting, mixing, and homogenization.

[0025] The carbonization process in step (2) is as follows: steel slag coarse aggregate with a particle size between 4.75 and 20 mm is evenly spread in a sealed blower carbonization silo, and the material layer thickness is controlled at 10 to 20 cm to ensure CO2 diffusion efficiency. A CO2 / air mixture with a CO2 volume concentration of 20% to 50% is introduced to carry out the carbonization reaction. The humidification and blower systems are turned on simultaneously to maintain the temperature inside the silo at 20 to 30°C and the relative humidity at 70% to 90%. The carbonization reaction lasts for 12 to 72 hours. During this period, the material is turned over 2 to 3 times by the turning system. The reaction is terminated when the pH of the steel slag coarse aggregate surface drops to 8 to 9. After discharge, the material is transferred to the drying silo by a belt conveyor and treated with natural air drying or a low-temperature drying process at ≤60°C until the moisture content is ≤1%.

[0026] (3) Using the undersize material in step (1) as the basic raw material, after crushing and grinding, the undersize material with a particle size of less than 0.075 mm is retained as the raw material for preparing carbide steel slag powder. The remaining particles with a particle size range of 0.075~4.75 mm are dried, dehydrated, carbonized, cooled and screened to obtain fine aggregate of carbide steel slag with a specific surface area of ​​200~600 m² / kg and a particle size range of 0.075~4.75 mm.

[0027] The drying temperature in step (3) is 80℃, and the moisture content of the dried material needs to be reduced to ≤1%.

[0028] The carbonization treatment method described in step (3) is the same as the carbonization treatment method for steel slag coarse aggregate in step (2);

[0029] (4) Using the undersize material with a particle size of less than 0.075 mm in step (3) as the core raw material, after drying and dehumidifying, and deep grinding to increase the specific surface area, the carbonization process is further activated and graded for purification to finally obtain a stable carbonized steel slag powder material.

[0030] The drying temperature in step (4) is 40~60℃, and the sieve material is dried to a moisture content of ≤0.5%; the specific surface area after deep grinding is 350~850m² / kg;

[0031] In step (4), an air classifier is used for classification and purification. The specific operation is as follows: adjust the speed of the classifier wheel to 2500~4000 r / min, control the negative pressure to -5~-10 kPa, separate the coarse particles with a particle size >0.075mm, return them to the furnace for secondary grinding, and collect the carbide steel slag powder material with a particle size <0.075mm.

[0032] The carbonization process described in step (4) is slurry carbonization: ultrafine steel slag powder dried to a moisture content of ≤0.5% is prepared into a slurry with a solid content of 30%~40%. After high-speed stirring (not less than 100r / min) for 10~15min, it is transferred to a high-pressure reactor. Pure CO2 is introduced to increase the pressure to 0.2~0.3 MPa and the temperature to 30~40℃. Microbubble aeration reaction is carried out for 2~6h. When the pH of the slurry stabilizes at 7.0~7.5, the reaction is terminated. After plate and frame filtration, drying at 50~60℃ to constant weight and cooling and sieving, carbonized steel slag powder is obtained.

[0033] Furthermore, the slag powder described in this invention is S95 grade granulated blast furnace slag powder, with a particle size range of 0.5~45μm and a specific surface area of ​​400~500m². 2 / kg, with high activity.

[0034] Furthermore, the fly ash described in this invention is Class F, Grade II fly ash, with a particle size range of 1~10μm and a specific surface area of ​​250~300m². 2 / kg.

[0035] Furthermore, the natural coarse aggregate of the present invention has a particle size of 4.75~20mm, and the fineness modulus of the river sand is 2.5~3.

[0036] Further, the alkali activator of the present invention is a mixed aqueous solution of water glass and sodium hydroxide; wherein the sodium hydroxide has a purity of over 99% and is a white powder solid; the water glass is sodium metasilicate nonahydrate, with a Na2O content of 8.74% and a SiO2 content of 27.64%. Preferably, the preparation method of the alkali activator includes: preparing a sodium hydroxide solution by mixing sodium hydroxide and water at a mass ratio of 1:1, stirring evenly, and then allowing it to stand for 12-24 hours in an environment with a temperature of 20-25°C and a humidity of 60-70%. Before the actual use of the alkali activator, the sodium hydroxide solution and water glass are mixed and stirred evenly to obtain an alkali activator with a target modulus of 1.0-1.8. For example, if the water glass and sodium hydroxide in the alkali activator of the present invention need to be prepared to achieve a target modulus of 1.2, the mass steps of sodium hydroxide required per 100g of water glass are as follows:

[0037] ①: The number of Na2O molecules per 100 grams in water glass = Na2O content / molecular weight = 8.74 / 62 = 0.141 mol;

[0038] ②: The number of SiO2 molecules per 100 grams in sodium silicate = SiO2 content / molecular weight = 27.64 / 60.1 = 0.460 mol;

[0039] ③: If the target modulus is 1.2, then the number of Na2O molecules per 100 grams = the number of SiO2 molecules per 100 grams / 1.2 = 0.460 / 1.2 = 0.383 mol;

[0040] ④: The number of Na2O molecules that need to be increased by adding sodium hydroxide is: the number of Na2O molecules per 100 grams in the water glass with the target mold size of 1.2 - the number of Na2O molecules per 100 grams in the original water glass = 0.383 - 0.141 = 0.242 mol;

[0041] ⑤: Based on the chemical equilibrium equation for the reaction between sodium silicate and sodium hydroxide in water:

[0042]

[0043] For every 1 mol Na₂O added to the left side of the above formula, 2 mol of sodium hydroxide are needed on the right side. Step ④ calculates that 0.242 mol of Na₂O is needed. Therefore, the number of sodium hydroxide molecules needed is 0.242 × 2 = 0.484 mol, which corresponds to a sodium hydroxide mass of 19.36 g. That is, when the sodium silicate used in this invention is adjusted to a modulus of 1.2 by adding sodium hydroxide, 100 g of silicate requires 19.36 g of sodium hydroxide.

[0044] Furthermore, the specific steps of the preparation method of the modified decommissioned wind turbine blade fiber of the present invention are as follows:

[0045] ① Use a cutting machine to cut large retired wind turbine blades into small block materials of 50~100mm. Use a jaw crusher combined with an impact crusher to mechanically crush the cut materials to form granular or flaky structures of 5~15mm.

[0046] ② High-pressure water washing is used to initially remove oil, dust and other pollutants from the surface of the blades; then, through a combination of physical methods such as mechanical grinding, high-speed stirring, airflow separation and vibrating sieving, the resin matrix is ​​broken by shear force, and recycled glass fibers with a length controllable between 6 and 12 mm are gradually separated.

[0047] The water pressure for the high-pressure water washing is 0.8~1.2 MPa;

[0048] The grinding speed is 300~500 r / min; the high-speed stirring speed is 800~1200 r / min; the air velocity during air separation is 10~15 m / s; and the screen aperture used in vibrating screening is 6~12 mm.

[0049] ③ Weigh out analytical grade NaOH and dissolve it in deionized water to prepare an alkaline treatment solution with a concentration of 2~4 mol / L; immerse the recycled glass fiber in the alkaline treatment solution at a solid-liquid ratio of 1:20~30, control the treatment temperature at 80~95℃, and soak for 10~20 minutes to achieve degumming and activation of the fiber surface;

[0050] ④ After draining the fibers, rinse them in a 0.5-1 mol / L HCl solution for 8-15 minutes to remove residual NaOH and impurities from the fiber surface. Then rinse them with deionized water 3-5 times and place them in a forced-air drying oven at 60-80℃ for 0.5-1.5 hours until the fiber moisture content is ≤0.5%.

[0051] ⑤ Prepare an aminopropyltriethoxysilane solution using aminopropyltriethoxysilane and deionized water at a volume ratio of 1:99, and let the prepared aqueous solution stand for 24 hours; immerse the fiber obtained in step ④ in the aminopropyltriethoxysilane solution for 15 minutes, remove it and drain off the excess solution on the surface to obtain the modified decommissioned wind turbine blade glass fiber of the present invention, ready for use.

[0052] Furthermore, the water-reducing agent of the present invention is selected from any one or a mixture of more than one of naphthalene-based high-efficiency water-reducing agents, modified polycarboxylate water-reducing agents, and melamine-formaldehyde condensates.

[0053] Furthermore, the retarder of the present invention is selected from any one or a mixture of one or more of sucrose, calcium lignosulfonate, citric acid, malic acid, and barium chloride.

[0054] Furthermore, this invention provides a method for preparing alkali-activated zero-cement solid waste heat-resistant concrete based on glass fiber reinforcement from decommissioned wind turbine blades, comprising the following steps:

[0055] (1) Weigh all materials according to the mix proportion and store them in a dry container. Prepare the alkali activator solution according to the measurement 30 minutes before pouring the concrete specimen. At the same time, add the water-reducing agent and retarder into the mixing water to make a water-water mixture. Stir until completely dissolved, seal and let stand for later use.

[0056] (2) Pour natural coarse aggregate, coarse aggregate of carbide steel slag, river sand, fine aggregate of carbide steel slag, 1 / 2 part by weight of slag powder, 1 / 2 part by weight of fly ash, and 1 / 2 part by weight of carbide steel slag powder into a mixer. After premixing at a speed of 60~80 r / min for 30 seconds, add modified decommissioned wind turbine blade glass fiber evenly while mixing, and continue mixing at 60~80 r / min for 0.5 min.

[0057] (3) Take 60%~70% of the weight of the water mixture from step (1), and slowly pour it into the mixer along with the alkali activator solution, and stir at 120~150 r / min for 1 min;

[0058] (4) Add the remaining 1 / 2 part by weight of fly ash, 1 / 2 part by weight of slag powder and 1 / 2 part by weight of carbide steel slag powder to the mixer, and stir at a speed of 120~150 r / min for 1 min;

[0059] (5) Pour the remaining 30%~40% by weight of water mixture from step (1) into the product stirred in step (4), and continue stirring at 120~150 r / min for 1 min. After discharging and testing the workability, cast the specimen.

[0060] (6) The concrete is poured into the mold, vibrated, and left to stand at room temperature for 24 hours before being demolded. Then it is placed in a standard curing box and cured for the specified age to obtain the alkali-activated zero cement solid waste heat-resistant concrete of the present invention.

[0061] This invention utilizes alkali-activated steel slag powder-mineral slag powder-fly ash ternary solid waste polymer cementitious material, solid waste steel slag from the metallurgical industry, modified decommissioned wind turbine blade glass fiber, and admixtures to prepare decommissioned wind turbine blade glass fiber reinforced alkali-activated zero-cement solid waste heat-resistant and radiation-proof concrete. The fire resistance and radiation protection mechanism of the heat-resistant and radiation-proof concrete of the present invention is as follows: (1) In terms of fire resistance and mechanical properties, it benefits from the multi-scale synergistic effect of solid waste "low thermal conductivity gel - high melting point aggregate - crack-resistant glass fiber": the M-(Si,Al)-O tetrahedral three-dimensional network formed by geopolymer has no crystal water, and the Si-O and Al-O bond energies are high, and it is still stable at 800℃; the carbonized steel slag powder in the ternary solid waste releases CO2 to relieve stress, the mineral powder forms a dense network, and the fly ash enhances the degree of crosslinking. The carbonized steel slag aggregate is a high melting point aggregate, which hardly melts at 600~1000℃, and can maintain the mechanical support of the aggregate skeleton; the glass fiber is randomly distributed to suppress cracks, and its elastic modulus is higher than that of alkali-activated cementitious materials. Under high temperature conditions, the structure is not easily deformed, which is conducive to maintaining the volume stability of concrete. (2) In terms of radiation protection performance, carbonized steel slag not only contains high atomic number elements such as Fe and Mn, but also enhances the shielding effect through conductive loss and interface reflection after being incorporated. Combined with the low porosity of less than 15% of geopolymer, it strengthens the attenuation of γ-rays according to the mass decay law. The glass fiber of the retired wind turbine blades is diffusely distributed and forms a complementary shield with the steel slag.

[0062] Compared with the prior art, the present invention has the following beneficial effects:

[0063] (1) This invention innovatively selects slag powder, fly ash, carbonized full-size graded steel slag, and modified decommissioned wind turbine blade fiber as core raw materials to successfully prepare a cement-free high-value concrete material. This material has excellent heat resistance, radiation protection performance, and environmental compatibility. It can be widely used in the construction of key infrastructure such as flues and piers in the metallurgical industry. Through in-situ co-treatment and self-disposal of metallurgical solid waste, it can significantly reduce the material preparation cost and improve the efficiency of industrial solid waste resource recycling. It can also be extended to various high-temperature radiation service environments in the field of civil engineering, providing an innovative solution that combines economy, environmental protection, and engineering practicality for the green and low-carbon transformation of the metallurgical industry, and helping to achieve the dual goals of solid waste resource utilization and low-carbon development.

[0064] (2) Achieving multi-scale synergistic effect of solid waste "low thermal conductivity gel - high melting point aggregate - crack-resistant glass fiber": Alkali-activated cementitious material achieves high temperature stability and heat insulation through chemical composition and microstructure, carbonized steel slag aggregate provides mechanical support and thermal inertia, and modified decommissioned wind turbine blade glass fiber inhibits cracks and maintains structural continuity. This synergistic effect endows the material with excellent fire resistance.

[0065] (3) The carbonization treatment in this invention can efficiently consume free calcium oxide in steel slag. f -CaO) and free magnesium oxide ( f The presence of Fe and Pb in the steel slag aggregate solves the volume expansion problem caused by hydration of both materials. Furthermore, the high density of the concrete, combined with the low porosity (less than 15%) of the geopolymer system, significantly enhances gamma-ray attenuation, strictly adhering to the law of mass decay and thus significantly improving radiation protection capabilities. Simultaneously, the steel slag possesses excellent electrical and interfacial properties, effectively enhancing electromagnetic shielding performance through a dual mechanism of conductive loss (converting electromagnetic energy into heat) and interfacial reflection (multiple scattering to reduce electromagnetic wave penetration). In addition, modified glass fibers derived from retired wind turbine blades are uniformly dispersed throughout the system, forming a complementary and synergistic shielding system with the steel slag aggregate, further optimizing the comprehensiveness and reliability of radiation protection. Detailed Implementation

[0066] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, they will be further described below, but the present invention is not limited to these embodiments.

[0067] An alkali-activated zero-cement solid waste heat-resistant concrete based on glass fiber reinforced decommissioned wind turbine blades comprises the following components in parts by weight:

[0068] 63-80 parts of slag powder

[0069] 25-35 parts fly ash

[0070] 5-20 parts of carbide steel slag powder

[0071] 92-136 parts natural coarse aggregate,

[0072] 138-204 parts of coarse aggregate made from carbide steel slag.

[0073] River sand 96-135 parts,

[0074] 64-90 parts of fine aggregate from carbide steel slag.

[0075] 45-60 parts water

[0076] 5-10 parts of alkali activator

[0077] Modified decommissioned wind turbine blades, 1-3 parts fiberglass,

[0078] Water-reducing agent 0.5-3 parts,

[0079] 0.5-3 parts of retarder;

[0080] The modified decommissioned wind turbine blade fiber is obtained by cutting, crushing, milling, and screening decommissioned wind turbine blades in sequence, and then modifying them with NaOH solution and aminopropyltriethoxysilane solution, with a length of 6~12mm.

[0081] The steel slag powder, coarse aggregate, and fine aggregate are all made from raw steel slag ore, which is obtained through crushing, screening, and carbonization. The raw steel slag ore originates from a metallurgical plant in Shanghai. The derived coarse steel slag aggregate (4.75~20mm), fine steel slag aggregate (0.075~4.75mm), and steel slag powder (<0.075mm) are all prepared through the following specific process:

[0082] (1) Using steel slag ore as raw material, the ore is crushed by a jaw crusher and then graded and screened. While removing impurities, the undersize material with a particle size of less than 4.75 mm is retained as raw material for fine aggregate of carbide steel slag and powder of carbide steel slag.

[0083] (2) In step (1), steel slag coarse aggregate with a sieve residue size of 4.75~20mm is obtained by grading and screening. It is then subjected to high-pressure water washing (to remove dust), pre-wetting mixing and homogenization, and carbonization treatment. Finally, carbonization product debris is removed by secondary screening to obtain standardized carbonized steel slag coarse aggregate with a specific surface area of ​​150~750 m² / kg and a density of 3.1~3.8 g / cm³.

[0084] In step (2), the moisture content of the steel slag coarse aggregate is controlled to be 10-15% through pre-wetting, mixing, and homogenization.

[0085] The carbonization process in step (2) is as follows: steel slag coarse aggregate with a particle size between 4.75 and 20 mm is evenly spread in a sealed blower carbonization silo, and the material layer thickness is controlled at 10 to 20 cm to ensure CO2 diffusion efficiency. A CO2 / air mixture with a CO2 volume concentration of 20% to 50% is introduced to carry out the carbonization reaction. The humidification and blower systems are turned on simultaneously to maintain the temperature inside the silo at 20 to 30°C and the relative humidity at 70% to 90%. The carbonization reaction lasts for 12 to 72 hours. During this period, the material is turned over 2 to 3 times by the turning system. The reaction is terminated when the pH of the steel slag coarse aggregate surface drops to 8 to 9. After discharge, the material is transferred to the drying silo by a belt conveyor and treated with natural air drying or a low-temperature drying process at ≤60°C until the moisture content is ≤1%.

[0086] (3) Using the undersize material in step (1) as the basic raw material, after crushing and grinding, the undersize material with a particle size of less than 0.075 mm is retained as the raw material for preparing carbide steel slag powder. The remaining particles with a particle size range of 0.075~4.75 mm are dried, dehydrated, carbonized, cooled and screened to obtain carbide steel slag fine aggregate with a particle size range of 0.075~4.75 mm and a specific surface area of ​​200~600 m² / kg.

[0087] The drying temperature in step (3) is 80℃, and the moisture content of the dried material needs to be reduced to ≤1%.

[0088] The carbonization treatment method described in step (3) is the same as the carbonization treatment method for steel slag coarse aggregate in step (2);

[0089] (4) Using the undersize material with a particle size of less than 0.075 mm in step (3) as the core raw material, after drying and dehumidifying, and deep grinding to increase the specific surface area, the carbonization process is further activated and graded for purification to finally obtain a stable carbonized steel slag powder material.

[0090] The drying temperature in step (4) is 40~60℃, and the sieve material is dried to a moisture content of ≤0.5%; the specific surface area after deep grinding is 350~850m² / kg;

[0091] In step (4), an air classifier is used for classification and purification. The specific operation is as follows: adjust the speed of the classifier wheel to 2500~4000 r / min, control the negative pressure to -5~-10 kPa, separate the coarse particles with a particle size >0.075mm, return them to the furnace for secondary grinding, and collect the carbide steel slag powder material with a particle size <0.075mm.

[0092] The carbonization process described in step (4) is slurry carbonization: ultrafine steel slag powder dried to a moisture content of ≤0.5% is prepared into a slurry with a solid content of 30%~40%. After high-speed stirring (not less than 100r / min) for 10~15min, it is transferred to a high-pressure reactor. Pure CO2 is introduced to increase the pressure to 0.2~0.3 MPa and the temperature to 30~40℃. Microbubble aeration reaction is carried out for 2~6h. When the pH of the slurry stabilizes at 7.0~7.5, the reaction is terminated. After plate and frame filtration, drying at 50~60℃ to constant weight and cooling and sieving, carbonized steel slag powder is obtained.

[0093] Furthermore, the slag powder described in this invention is S95 grade granulated blast furnace slag powder, with a particle size range of 0.5~45μm and a specific surface area of ​​400~500m². 2 / kg, with high activity.

[0094] Furthermore, the fly ash described in this invention is Class F, Grade II fly ash, with a particle size range of 1~10μm and a specific surface area of ​​250~300m². 2 / kg.

[0095] Furthermore, the natural coarse aggregate of the present invention has a particle size of 4.75~20mm, and the fineness modulus of the river sand is 2.5~3.

[0096] Further, the alkali activator of the present invention is a mixed aqueous solution of water glass and sodium hydroxide; wherein the sodium hydroxide has a purity of over 99% and is a white powder solid; the water glass is sodium metasilicate nonahydrate, with a Na2O content of 8.74% and a SiO2 content of 27.64%. Preferably, the preparation method of the alkali activator includes: preparing a sodium hydroxide solution by mixing sodium hydroxide and water at a mass ratio of 1:1, stirring evenly, and then allowing it to stand for 12-24 hours in an environment with a temperature of 20-25°C and a humidity of 60-70%. Before the actual use of the alkali activator, the sodium hydroxide solution and water glass are mixed and stirred evenly to obtain an alkali activator with a target modulus of 1.0-1.8. For example, if the water glass and sodium hydroxide in the alkali activator of the present invention need to be prepared to achieve a target modulus of 1.2, the mass steps of sodium hydroxide required per 100g of water glass are as follows:

[0097] ①: The number of Na2O molecules per 100 grams in water glass = Na2O content / molecular weight = 8.74 / 62 = 0.141 mol;

[0098] ②: The number of SiO2 molecules per 100 grams in sodium silicate = SiO2 content / molecular weight = 27.64 / 60.1 = 0.460 mol;

[0099] ③: If the target modulus is 1.2, then the number of Na2O molecules per 100 grams = the number of SiO2 molecules per 100 grams / 1.2 = 0.460 / 1.2 = 0.383 mol;

[0100] ④: The number of Na2O molecules that need to be increased by adding sodium hydroxide is: the number of Na2O molecules per 100 grams in the water glass with the target mold size of 1.2 - the number of Na2O molecules per 100 grams in the original water glass = 0.383 - 0.141 = 0.242 mol;

[0101] ⑤: Based on the chemical equilibrium equation for the reaction between sodium silicate and sodium hydroxide in water:

[0102]

[0103] For every 1 mol Na₂O added to the left side of the above formula, 2 mol of sodium hydroxide are needed on the right side. Step ④ calculates that 0.242 mol of Na₂O is needed. Therefore, the number of sodium hydroxide molecules needed is 0.242 × 2 = 0.484 mol, which corresponds to a sodium hydroxide mass of 19.36 g. That is, when the sodium silicate used in this invention is adjusted to a modulus of 1.2 by adding sodium hydroxide, 100 g of silicate requires 19.36 g of sodium hydroxide.

[0104] Furthermore, the specific steps of the preparation method of the modified decommissioned wind turbine blade fiber of the present invention are as follows:

[0105] ① Use a cutting machine to cut large retired wind turbine blades into small block materials of 50~100mm. Use a jaw crusher combined with an impact crusher to mechanically crush the cut materials to form granular or flaky structures of 5~15mm.

[0106] ② High-pressure water washing is used to initially remove oil, dust and other pollutants from the surface of the blades; then, through a combination of physical methods such as mechanical grinding, high-speed stirring, airflow separation and vibrating sieving, the resin matrix is ​​broken by shear force to gradually separate recycled glass fibers with a length controllable between 6 and 12 mm.

[0107] The water pressure for the high-pressure water washing is 0.8~1.2MPa;

[0108] The grinding speed is 300~500 r / min; the high-speed stirring speed is 800~1200 r / min; the air velocity during air separation is 10~15 m / s; and the screen aperture used in vibrating screening is 6~12 mm.

[0109] ③ Weigh out analytical grade NaOH and dissolve it in deionized water to prepare an alkaline treatment solution with a concentration of 2~4 mol / L; immerse the recycled glass fiber in the alkaline treatment solution at a solid-liquid ratio of 1:20~30, control the treatment temperature at 80~95℃, and soak for 10~20 minutes to achieve degumming and activation of the fiber surface;

[0110] ④ After draining the fibers, rinse them in a 0.5-1 mol / L HCl solution for 8-15 minutes to remove residual NaOH and impurities from the fiber surface. Then rinse them with deionized water 3-5 times and place them in a forced-air drying oven at 60-80℃ for 0.5-1.5 hours until the fiber moisture content is ≤0.5%.

[0111] ⑤ Prepare an aminopropyltriethoxysilane solution using aminopropyltriethoxysilane and deionized water at a volume ratio of 1:99, and let the prepared aqueous solution stand for 24 hours; immerse the fiber obtained in step ④ in the aminopropyltriethoxysilane solution for 15 minutes, remove it and drain off the excess solution on the surface to obtain the modified decommissioned wind turbine blade glass fiber of the present invention, ready for use.

[0112] Furthermore, the water-reducing agent of the present invention is selected from any one or a mixture of more than one of naphthalene-based high-efficiency water-reducing agents, modified polycarboxylate water-reducing agents, and melamine-formaldehyde condensates.

[0113] Furthermore, the retarder of the present invention is selected from any one or a mixture of one or more of sucrose, calcium lignosulfonate, citric acid, malic acid, and barium chloride.

[0114] Furthermore, this invention provides a method for preparing alkali-activated zero-cement solid waste heat-resistant concrete based on glass fiber reinforcement from decommissioned wind turbine blades, comprising the following steps:

[0115] (1) Weigh all materials according to the mix proportion and store them in a dry container. Prepare the alkali activator solution according to the measurement 30 minutes before pouring the concrete specimen. At the same time, add the water-reducing agent and retarder into the mixing water to make a water-water mixture. Stir until completely dissolved, seal and let stand for later use.

[0116] (2) Pour natural coarse aggregate, coarse aggregate of carbide steel slag, river sand, fine aggregate of carbide steel slag, 1 / 2 part by weight of slag powder, 1 / 2 part by weight of fly ash, and 1 / 2 part by weight of carbide steel slag powder into a mixer. After premixing at a speed of 60~80r / min for 30s, add the glass fiber of retired wind turbine blades evenly while mixing, and continue mixing at 60~80r / min for 0.5min.

[0117] (3) Take 60%~70% of the weight of the water mixture from step (1), and slowly pour it into the mixer along with the alkali activator solution, and stir at 120~150 r / min for 1 min;

[0118] (4) Add the remaining 1 / 2 part by weight of fly ash, 1 / 2 part by weight of slag powder and 1 / 2 part by weight of carbide steel slag powder to the mixer, and stir at a speed of 120~150 r / min for 1 min;

[0119] (5) Pour the remaining 30%~40% by weight of water mixture from step (1) into the product stirred in step (4), and continue stirring at 120~150 r / min for 1 min. After discharging and testing the workability, cast the specimen.

[0120] (6) The concrete is poured into the mold, vibrated, and left to stand at room temperature for 24 hours before being demolded. Then it is placed in a standard curing box and cured for the specified age to obtain the alkali-activated zero cement solid waste heat-resistant concrete of the present invention.

[0121] Example 1

[0122] A heat-resistant alkali-activated zero-cement solid waste concrete based on glass fiber reinforcement of decommissioned wind turbine blades comprises the following components by weight fraction: 65 parts slag powder, 33 parts fly ash, 10 parts steel slag powder, 128 parts natural coarse aggregate, 192 parts steel slag coarse aggregate, 117 parts river sand, 78 parts steel slag fine aggregate, 50 parts water, 10 parts alkali activator (8.5 parts water glass, 1.3 parts analytical grade sodium hydroxide), 1.5 parts modified decommissioned wind turbine blade glass fiber, 2.5 parts water-reducing agent, and 0.6 parts retarder;

[0123] The water-reducing agent used is SBTJM®-A naphthalene-based high-efficiency water-reducing agent produced by Jiangsu Subote New Material Co., Ltd., and the retarder is sucrose.

[0124] The replacement rate of coarse aggregate from steel carbide slag is 60%, and that of fine aggregate from steel carbide slag is 40%.

[0125] The specific steps of the preparation method are as follows:

[0126] (1) Alkali activator treatment:

[0127] First, prepare a sodium hydroxide solution 12-24 hours in advance. Mix analytical grade sodium hydroxide and water in a 1:1 mass ratio and place it in an environment with a temperature of 20℃ and a humidity of 60%. 30 minutes before pouring the concrete mixture, mix the sodium hydroxide solution with water glass solution according to the ratio, with a modulus of 1.2 and an alkali content of 6%, and stir well.

[0128] (2) Fiberglass modification treatment of decommissioned wind turbine blades:

[0129] ① Large decommissioned wind turbine blades are cut into small blocks of 50-100mm using a cutting machine. A jaw crusher combined with an impact crusher is then used to mechanically crush the cut material, forming granular or flaky structures of 5-15mm. ② The raw material is initially cleaned of oil, dust, and other contaminants using 1.0 MPa high-pressure water washing. Then, a combined physical process of mechanical grinding (400 r / min), high-speed stirring (1000 r / min), airflow separation (12 m / s), and vibrating sieving (6-12mm mesh size) is employed to break down the resin matrix through shearing, separating recycled glass fibers with a controllable length of 6-12mm. ③ NaOH granules are dissolved in deionized water to prepare a 3 mol / L alkali treatment solution. The recycled glass fibers are immersed in the solution at a solid-liquid ratio of 1:25, with the treatment temperature controlled at 90℃ and the immersion time 15 minutes. min, to achieve degumming and activation of the fiber surface; ④ After draining the fiber, it is placed in a 0.8 mol / L HCl solution for acid washing and neutralization to remove residual NaOH and impurities on the fiber surface, then rinsed 3 times with deionized water, and placed in a forced-air drying oven at 60℃ for 1 h until the fiber moisture content is ≤0.5%; ⑤ Prepare an aminopropyltriethoxysilane solution using an aminopropyltriethoxysilane:deionized water volume ratio of 1:99, and let the prepared aqueous solution stand for 24 hours; ⑥ Immerse the fiber obtained after treatment with sodium hydroxide solution in the aminopropyltriethoxysilane solution for 15 minutes, remove it and drain the excess solution on the surface, and set aside for use.

[0130] (3) Preparation of coarse and fine aggregates of steel carbide slag and steel carbide slag powder:

[0131] ① Using steel slag ore as the initial raw material, a jaw crusher is first used to crush and pre-treat it. Then, the material is classified and purified through a grading and screening process: while removing impurities from the screening system, the undersize components with a particle size of less than 4.75 mm are collected and used as raw materials for fine aggregates and powders of carbide steel slag.

[0132] ② For steel slag coarse aggregate with a particle size of 4.75~20 mm after screening, the following treatments were carried out in sequence: First, high-pressure water washing was used to remove dust from the surface of the aggregate; then, pre-wetting and homogenization treatment was carried out to control the moisture content of the material to 10%~15%; then carbonization modification was carried out: the steel slag coarse aggregate was evenly spread in a sealed blower carbonization chamber, and the thickness of the material layer was adjusted to 10cm to ensure the mass transfer and diffusion efficiency of CO2. A CO2 / air mixture with a CO2 volume concentration of 25% was introduced into the chamber, and the humidification and blower systems were started simultaneously to maintain the environmental parameters in the chamber at a temperature of 20~30℃ and a relative humidity of 80%; the carbonization reaction lasted for 24 hours, and the material was turned over twice by the turning system during the period; the carbonization reaction was terminated when the pH value of the aggregate surface dropped to 8~9. After the reaction, the material is transferred to the drying chamber by a belt conveyor and is treated by natural air drying or low temperature drying at ≤60℃ until the moisture content is ≤1%. Finally, the product debris generated during the carbonization process is removed by secondary screening, and the particle size distribution of the material is precisely controlled to obtain standardized carbonized steel slag coarse aggregate with a specific surface area of ​​150~750 m² / kg and a density of 3.1~3.8 g / cm³.

[0133] ③ Using the undersize material from step ① as the base material, after crushing and grinding, it is graded and screened. The undersize material with a particle size less than 0.075 mm is retained as the raw material for preparing carbide steel slag powder. The remaining particles in the particle size range of 0.075~4.75 mm are subjected to subsequent processing: First, drying and dehydration are carried out, and the drying temperature is controlled at 80℃ to ensure that the moisture content of the material after drying is reduced to 1% or less; then, carbonization modification treatment is carried out using the same process parameters as the coarse aggregate; after modification, cooling and screening processes are carried out to finally obtain fine aggregate of carbide steel slag with a particle size range of 0.075~4.75 mm and a specific surface area of ​​200~600 m² / kg.

[0134] ④ Using the sieve undersize material with a particle size of less than 0.075 mm from step ③ as the core raw material, after drying and dehumidifying at 50℃ and deep grinding to a specific surface area of ​​350~850 m² / kg, the material is further activated by carbonization treatment and purified by air classifier (classifier wheel speed 4000 r / min, negative pressure -5 kPa). Coarse particles >0.075 mm are separated and returned to the furnace for regrinding, while particles <0.075 mm are collected to obtain stable carbonized steel slag powder material.

[0135] Carbonization treatment method: Ultrafine powder with a moisture content of ≤0.5% is mixed into a slurry with a solid content of 40%, stirred at high speed (not less than 100 r / min) for 10 min, and then transferred to a high-pressure reactor. Pure CO2 is introduced to 0.25 MPa and micro-bubble aeration is carried out at 35℃ for 4 h. The reaction is terminated when the pH of the slurry stabilizes at 7.5. The product is filtered by plate and frame filter press, dried at 55℃ to constant weight, cooled and sieved to finally obtain carbonized steel slag powder with stable performance.

[0136] (4) Preparation of alkali-activated zero-cement solid waste heat-resistant and radiation-proof concrete based on glass fiber reinforced decommissioned wind turbine blades:

[0137] ① Weigh out the following components according to the specified proportions: slag powder, fly ash, carbide steel slag powder, natural coarse aggregate, carbide steel slag coarse aggregate, carbide steel slag fine aggregate, river sand, modified decommissioned wind turbine blade fiberglass, sodium hydroxide solution, water glass, retarder, and water-reducing agent. 30 minutes before pouring, mix the sodium hydroxide solution and water glass evenly to prepare an alkali activator, and let it stand for later use. At the same time, mix the water-reducing agent and retarder with water evenly to prepare an aqueous mixture, and set it aside for later use.

[0138] ② Add natural coarse aggregate, coarse aggregate of steel slag, fine aggregate of steel slag, river sand, and 1 / 2 dose of slag powder, 1 / 2 dose of fly ash, and 1 / 2 dose of steel slag powder to the mixer and stir for half a minute. While stirring, pour in the decommissioned wind turbine blade fiber evenly and stir at a speed of 60 r / min for half a minute.

[0139] ③ Slowly pour in the mixture of alkali activator and 60%~70% water, and continue stirring at 125r / min for 1 minute;

[0140] ④ Add the remaining mineral powder, fly ash, and carbide steel slag powder, and continue stirring for 1 minute at the stirring speed of step ③;

[0141] ⑤ Pour in the remaining water mixture and stir at the same speed as in step ④ for 1 minute until the mixture is homogeneous;

[0142] ⑥ Pour the concrete mixture into the mold, vibrate it to compact it, let it stand at room temperature for 24 hours before demolding, and then place it in a standard curing box to cure it to the specified age, thus obtaining alkali-activated zero-cement solid waste heat-resistant and radiation-proof concrete based on glass fiber reinforcement of retired wind turbine blades.

[0143] Example 2

[0144] A heat-resistant alkali-activated zero-cement solid waste concrete based on glass fiber reinforcement of decommissioned wind turbine blades comprises the following components by weight: 63 parts slag powder, 25 parts fly ash, 5 parts carbide steel slag powder, 92 parts natural coarse aggregate, 138 parts steel slag coarse aggregate, 96 parts river sand, 64 parts carbide steel slag fine aggregate, 45 parts water, 5 parts alkali activator (4.3 parts water glass and 0.7 parts sodium hydroxide analytical grade), 1.5 parts modified decommissioned wind turbine blade glass fiber, 2.3 parts water-reducing agent, and 0.5 parts retarder;

[0145] The water-reducing agent used is modified polycarboxylate water-reducing agent (PCA®-Ⅲ polycarboxylate high slump-retention water-reducing agent produced by Jiangsu Subote New Material Co., Ltd.), and the retarder is calcium lignosulfonate.

[0146] The replacement rate of coarse aggregate from steel carbide slag is 60%, and that of fine aggregate from steel carbide slag is 40%.

[0147] The specific steps of the preparation method are as follows:

[0148] (1) Alkali activator treatment:

[0149] First, prepare a sodium hydroxide solution 12-24 hours in advance. Mix analytical grade sodium hydroxide and water in a 1:1 mass ratio and place it in an environment with a temperature of 25℃ and a humidity of 70%. 30 minutes before pouring the concrete mixture, mix the sodium hydroxide solution with water glass solution according to the ratio, with a modulus of 1.5 and an alkali content of 6%, and stir well.

[0150] (2) Fiberglass modification treatment of decommissioned wind turbine blades:

[0151] ① Use a cutting machine to cut large decommissioned wind turbine blades into small blocks of 50-100mm. Use a jaw crusher combined with an impact crusher to mechanically crush the cut materials, forming granular or flake structures of 5-15mm. ② Use high-pressure water washing (1.2 MPa) to initially remove oil, dust, and other contaminants from the blade surface. Then, use a combined physical method of mechanical grinding (500 r / min), high-speed stirring (800 r / min), airflow separation (15 m / s), and vibrating sieving (6-12 mm mesh size) to break down the resin matrix using shear force, gradually separating recycled glass fibers with a controllable length of 6-12 mm. ③ Dissolve analytical grade NaOH in deionized water to prepare a 4 mol / L alkali treatment solution. Immerse the recycled glass fibers in the solution at a solid-liquid ratio of 1:20, controlling the treatment temperature at 95℃ for 10 minutes to achieve degumming and activation of the fiber surface. ④ After draining the fibers, immerse them in a 1% alkali solution. The fiber was neutralized by acid washing in mol / L HCl solution for 8 min to remove residual NaOH and impurities from the fiber surface. It was then rinsed three times with deionized water and placed in a forced-air drying oven at 60-80℃ for 1.5 h until the fiber moisture content was ≤0.5%. ⑤ An aminopropyltriethoxysilane solution was prepared using an aminopropyltriethoxysilane:deionized water volume ratio of 1:99. The prepared aqueous solution was allowed to stand for 24 hours. ⑥ The fiber obtained after treatment with sodium hydroxide solution was immersed in the aminopropyltriethoxysilane solution for 15 minutes. After removal, excess solution was drained from the surface and the fiber was ready for use.

[0152] (3) The preparation of coarse and fine aggregates of carbonized steel slag, steel slag powder and the concrete are the same as in Example 1.

[0153] Example 3

[0154] A heat-resistant alkali-activated zero-cement solid waste concrete based on glass fiber reinforcement of decommissioned wind turbine blades comprises the following components by weight: 70 parts slag powder, 30 parts fly ash, 15 parts carbide steel slag powder, 125 parts natural coarse aggregate, 176 parts steel slag coarse aggregate, 118 parts river sand, 76 parts carbide steel slag fine aggregate, 57 parts water, 7.5 parts alkali activator (3.8 parts water glass, 0.2 parts analytical grade sodium hydroxide), 2 parts modified decommissioned wind turbine blade glass fiber, 2.4 parts water-reducing agent, and 0.6 parts retarder;

[0155] The water-reducing agent used is melamine-formaldehyde condensate, and the retarder used is calcium lignosulfonate;

[0156] The replacement rate of coarse aggregate from steel carbide slag is 60%, and that of fine aggregate from steel carbide slag is 40%.

[0157] The specific steps of the preparation method are as follows:

[0158] (1) Alkali activator treatment:

[0159] First, prepare a sodium hydroxide solution 12-24 hours in advance. Mix analytical grade sodium hydroxide and water in a 1:1 mass ratio and place it in an environment with a temperature of 23℃ and a humidity of 70%. 30 minutes before pouring the concrete mixture, mix the sodium hydroxide solution with water glass solution according to the ratio, with a modulus of 1.8 and an alkali content of 6%, and stir well.

[0160] (2) Fiberglass modification treatment of decommissioned wind turbine blades:

[0161] ① Large decommissioned wind turbine blades are cut into small blocks of 50-100mm using a cutting machine. A jaw crusher combined with an impact crusher is then used to mechanically crush the cut materials, forming granular or flaky structures of 5-15mm. ② High-pressure water washing (1.2 MPa) is used to initially remove oil, dust, and other contaminants from the blade surface. Then, a combined physical method of mechanical grinding (500 r / min), high-speed stirring (800 r / min), airflow separation (15 m / s), and vibrating sieving (6-12 mm mesh) is employed to break down the resin matrix using shear force, gradually separating recycled glass fibers with a controllable length of 6-12 mm. ③ Analytical grade NaOH is dissolved in deionized water to prepare a 4 mol / L alkali treatment solution. The recycled glass fibers are immersed in the solution at a solid-liquid ratio of 1:20, with the treatment temperature controlled at 95℃ and the immersion time at 10 min to achieve degumming and activation of the fiber surface. ④ After draining the fibers, they are immersed in a 1% alkali solution. The fiber was neutralized by acid washing in a mol / L HCl solution for 8 min to remove residual NaOH and impurities from the fiber surface. It was then rinsed 5 times with deionized water and placed in a forced-air drying oven at 75℃ for 1.5 h until the fiber moisture content was ≤0.5%. ⑤ An aminopropyltriethoxysilane solution was prepared using an aminopropyltriethoxysilane:deionized water volume ratio of 1:99. The prepared aqueous solution was allowed to stand for 24 hours. ⑥ The fiber obtained after treatment with sodium hydroxide solution was immersed in the aminopropyltriethoxysilane solution for 10 minutes, removed, and excess solution was drained off before use.

[0162] (3) Preparation of coarse and fine aggregates of steel carbide slag and steel carbide slag powder:

[0163] ① Using steel slag ore as raw material, the ore is crushed by a jaw crusher and then graded and screened to remove impurities. The undersize material smaller than 4.75mm is retained as steel slag fine aggregate raw material.

[0164] ② Coarse aggregate with a sieve residue size between 4.75 and 20 mm is sequentially subjected to high-pressure water washing (to remove dust from the aggregate surface), premixing and homogenization (moisture content controlled at 10% to 15%), and carbonization treatment (the steel slag aggregate is evenly spread in a sealed blower carbonization chamber, the material layer thickness is controlled at 10 cm to ensure CO2 diffusion efficiency, a CO2 / air mixture with a CO2 volume concentration of 25% is introduced, and the humidification and blower systems are turned on simultaneously to maintain the temperature inside the chamber at 25℃ and the relative humidity at 80%; the carbonization reaction lasts for 56 hours, during which the material is turned over 3 times by the turning system, and the reaction is terminated when the pH of the aggregate surface drops to 8. After discharge, the material is transferred to the drying chamber by a belt conveyor and treated with natural air drying or a low-temperature drying process at ≤60℃ until the moisture content is ≤1%). Finally, the carbonization product debris is removed by secondary screening and the particle size distribution is precisely controlled to obtain standardized carbonized steel slag coarse aggregate with a specific surface area of ​​550 m² / kg and a density of 3.1 to 3.8 g / cm³.

[0165] ③ Using the undersize material from step ① as the base material, after crushing and grinding, it is graded and screened. The undersize material with a particle size less than 0.075 mm is retained as the raw material for preparing carbide steel slag powder. The remaining particles in the particle size range of 0.075~4.75 mm are subjected to subsequent processing: First, drying and dehydration are carried out, and the drying temperature is controlled at 60℃ to ensure that the moisture content of the material after drying is reduced to 1% or less; then, carbonization modification treatment is carried out using the same process parameters as the coarse aggregate; after modification, cooling and screening processes are carried out to finally obtain fine aggregate of carbide steel slag with a particle size range of 0.075~4.75 mm and a specific surface area of ​​200~600 m² / kg.

[0166] ④ Using the undersize material with a particle size of less than 0.075 mm from step ③ as the core raw material, after drying and dehumidifying at 50℃ and deep grinding to a specific surface area of ​​350~850 m² / kg, the material is further activated by carbonization treatment and purified by air classifier (classifier wheel speed 2500 r / min, negative pressure -10 kPa). Coarse particles >0.075 mm are separated and returned to the furnace for regrinding, while particles <0.075 mm are collected to obtain stable carbonized steel slag powder material.

[0167] Carbonization treatment method: Ultrafine powder with a moisture content of ≤0.5% is mixed into a slurry with a solid content of 40%, stirred at high speed (not less than 100 r / min) for 10 min, and then transferred to a high-pressure reactor. Pure CO2 is introduced to 0.25 MPa and micro-bubble aeration is carried out at 35℃ for 2 h. The reaction is terminated when the pH of the slurry stabilizes at 7.5. The product is filtered by plate and frame filter press, dried at 55℃ to constant weight, cooled and sieved to finally obtain carbonized steel slag powder with stable performance.

[0168] The method for preparing the concrete is the same as in Example 1.

[0169] Example 4

[0170] A heat-resistant alkali-activated zero-cement solid waste concrete based on glass fiber reinforcement of decommissioned wind turbine blades comprises the following components by weight fraction: 80 parts slag powder, 35 parts fly ash, 20 parts carbide steel slag powder, 136 parts natural coarse aggregate, 204 parts steel slag coarse aggregate, 135 parts river sand, 90 parts carbide steel slag fine aggregate, 60 parts water, 7.5 parts alkali activator (3.8 parts water glass, 0.2 parts analytical grade sodium hydroxide), 3 parts modified decommissioned wind turbine blade glass fiber, 2.8 parts water-reducing agent, and 0.5 parts retarder;

[0171] The water-reducing agent used is melamine-formaldehyde condensate, and the retarder used is calcium lignosulfonate;

[0172] The replacement rate of coarse aggregate from steel carbide slag is 60%, and that of fine aggregate from steel carbide slag is 40%.

[0173] The alkali activator, the steel slag modification method, the glass fiber modification treatment of retired wind turbine blades, and the concrete preparation method are the same as in Example 1.

[0174] Comparative Example 1

[0175] The dosage and preparation method of each component are mostly the same as in Example 1, except that the replacement rate of coarse aggregate of carbide steel slag is 0%, that is, 0 parts of coarse aggregate of carbide steel slag and 320 parts of natural coarse aggregate.

[0176] Comparative Example 2

[0177] The dosage and preparation method of each component are mostly the same as in Example 1, except that the replacement rate of coarse aggregate with carbide steel slag is 20%, that is, 64 parts of coarse aggregate with carbide steel slag and 256 parts of natural coarse aggregate.

[0178] Comparative Example 3

[0179] The dosage and preparation method of each component are mostly the same as in Example 1, except that the replacement rate of coarse aggregate with carbide steel slag is 40%, that is, 128 parts of coarse aggregate with carbide steel slag and 192 parts of natural coarse aggregate.

[0180] Comparative Example 4

[0181] The dosage and preparation method of each component are mostly the same as in Example 1, except that the replacement rate of coarse aggregate with carbide steel slag is 80%, that is, 256 parts of coarse aggregate with carbide steel slag and 64 parts of natural coarse aggregate.

[0182] Comparative Example 5

[0183] The dosage and preparation method of each component are mostly the same as in Example 1, except that the coarse aggregate of carbonized steel slag is replaced by an equal amount of uncarbonized steel slag coarse aggregate.

[0184] Comparative Example 6

[0185] The dosage and preparation method of each component are mostly the same as in Example 1, except that the replacement rate of fine aggregate of carbide steel slag is 0%, that is, 0 parts of fine aggregate of carbide steel slag and 195 parts of river sand.

[0186] Comparative Example 7

[0187] The dosage and preparation method of each component are mostly the same as in Example 1, except that the replacement rate of fine aggregate of carbide steel slag is 20%, that is, 39 parts of fine aggregate of carbide steel slag and 156 parts of river sand.

[0188] Comparative Example 8

[0189] The dosage and preparation method of each component are mostly the same as in Example 1, except that the replacement rate of fine aggregate of carbide steel slag is 60%, that is, 117 parts of fine aggregate of carbide steel slag and 78 parts of river sand.

[0190] Comparative Example 9

[0191] The dosage and preparation method of each component are mostly the same as in Example 1, except that the fine aggregate of carbonized steel slag is replaced by an equal amount of fine aggregate of steel slag that has not undergone carbonization treatment.

[0192] Comparative Example 10

[0193] The dosage and preparation method of each component are mostly the same as in Example 1. The difference is that the aggregates used are all natural coarse aggregates and river sand, namely 0 parts of coarse aggregates of carbonized steel slag, 320 parts of natural coarse aggregates, 0 parts of fine aggregates of carbonized steel slag, and 78 parts of river sand.

[0194] Comparative Example 11

[0195] The dosage and preparation method of each component are mostly the same as in Example 1, except that modified decommissioned wind turbine blade glass fiber is not added.

[0196] Comparative Example 12

[0197] The dosage and preparation method of each component are mostly the same as those in Example 1. The difference is that after the decommissioned wind turbine blades were treated by steps ① and ② in Example 1, steps ③, ④, ⑤, and ⑥ were not performed.

[0198] Comparative Example 13

[0199] The dosage and preparation method of each component are mostly the same as in Example 1, except that the carbonized steel slag powder is replaced by an equal amount of steel slag powder that has not undergone carbonization treatment.

[0200] Workability, apparent density, drying shrinkage, cracking, mechanical properties before and after high temperature, and radiation shielding were tested for each group of concrete. The specific test methods are as follows:

[0201] (a) Testing the workability of concrete mixtures:

[0202] According to the test methods in GB / T 50080-2016, the slump, spread and setting time of fresh concrete were tested. Since the setting time of alkali-activated concrete is shorter than that of ordinary concrete, the test was conducted every 5 minutes.

[0203] (II) Testing of the drying shrinkage and cracking properties of the above-mentioned heat-resistant and radiation-proof concrete:

[0204] According to the test method in standard GB / T 29419-7-2012, the heat-resistant and radiation-proof concrete of this invention was tested using an HSP-540 concrete shrinkage and expansion instrument. After demolding, the specimens were placed in a saturated CH solution for curing for 2 days, and the initial length was measured. L 0. Finally, the specimens were placed in a dry container at a temperature of (23±2)℃ and a relative humidity of (50±3)%, and the length of the specimens at the corresponding age was measured. L t Use shrinkage rate The degree of shrinkage of the specimen is indicated by the following formula:

[0205] (1)

[0206] The width and length of cracks in the concrete slab were detected using an integrated concrete crack detector (BJLF-1). First, the mixture was poured into a flat mold measuring 800 mm × 600 mm × 100 mm and vibrated. Then, the mold was moved to a condition with a relative humidity of 60 ± 5% and a temperature of 20 ± 2℃. If initial cracks occurred, the cracking process was continuously monitored for 24 hours. The cracking parameters of the concrete were obtained, such as the average crack area per unit area (…). a c ), number of cracks per unit area ( u unit ) and total area of ​​cracks per unit area ( A c It can be calculated based on the equation:

[0207] (2)

[0208] (3)

[0209] (4)

[0210] in, W i and L i These represent the crack width and length, respectively. A It is the area of ​​the flat plate; N It represents the total number of cracks.

[0211] (III) Testing of the fire resistance and mechanical properties of the above-mentioned heat-resistant and radiation-proof concrete:

[0212] After the specimens reached the required curing age, the compressive strength of the aforementioned heat-resistant and radiation-proof concrete specimens, measuring 100mm × 100mm × 100mm, was tested. Additionally, the specimens underwent high-temperature testing in an RX3-45-9 industrial resistance furnace. This furnace has a rated temperature of 1200℃, and thermocouples inside can monitor the furnace temperature in real time. The control box is equipped with a display screen showing the real-time furnace temperature. The furnace dimensions are 1200mm × 600mm × 400mm. The target temperatures for the high-temperature tests were 200℃, 400℃, 600℃, and 800℃. After heating to the target temperature at a rate of 10℃ / min, the temperature was maintained for 4 hours. Immediately after heating, the power was turned off, and the specimens were allowed to cool to room temperature with the furnace before being removed for compressive strength testing. Before the high-temperature test, the specimens were dried to constant weight in a drying oven, and their volume was measured with a ruler to determine their apparent density. Before each batch of specimens was subjected to high-temperature treatment, three specimen blocks were weighed using an electronic scale and their weights were recorded for comparison with the weights after high-temperature treatment.

[0213] (5)

[0214] (6)

[0215] Where F and A1 are the maximum load (N) and the stress area (mm) of the concrete specimen at failure, respectively; m 0、 m i , These represent the mass of the specimen before high temperature, the mass of the specimen after high temperature, and the mass loss rate, respectively.

[0216] (iv) Testing of the radiation protection performance of the above-mentioned heat-resistant and radiation-proof concrete:

[0217] After the specimens have been cured to the specified age, their shielding performance against gamma rays and neutron flux is characterized primarily by measuring the strength attenuation before and after radiation penetrates a concrete specimen of a specific thickness (300 mm × 300 mm × 100 mm). This invention uses cobalt-60 (… 60 Co was used as the γ-ray radiation source (activity 25.0 mCi), and the FJ-47A X-γ dosimeter was used as the detection instrument. The specific test procedure is as follows: the distance between the front of the heat-resistant and radiation-proof concrete slab and the radiation source was set to 40 cm, and the distance between the back and the dosimeter detection end was controlled to 5 cm. The radiation absorbed dose rate of the concrete slab was measured by the instrument, and the half-attenuation thickness and linear absorption coefficient of the material were derived by combining theoretical calculation methods.

[0218] (7)

[0219] (8)

[0220] In the formula: 1 0、 1 The strength of concrete before and after gamma rays pass through it, respectively; is the linear absorption coefficient of parallel single-energy gamma rays; x is the required thickness of the concrete material.

[0221] The concrete performance tests for each embodiment and comparative example are shown in Tables 1-5.

[0222] Table 1. Workability of fresh concrete mixtures from Examples 1-4 and Comparative Examples 1-13

[0223]

[0224] As can be seen from the performance data in Table 1:

[0225] The workability of the fresh concrete in Examples 1-4 is quite similar: the initial slump is concentrated between 160 and 167 mm, the initial spread is in the range of 542 to 549 mm, the initial setting time fluctuates between 113 and 121 min, and the final setting time is between 348 and 360 min. The differences in each indicator are relatively small.

[0226] Furthermore, as shown in Table 1, the data from Example 1 and Comparative Examples 1-4 indicate that with the increase of the coarse aggregate content of steel slag (0-60%), the initial slump and spread of the concrete mixture both improved. This is because the "smooth surface effect" and "low water absorption effect" of steel slag dominate. With the increase of the content, the overall friction of the aggregate decreases, the utilization rate of mixing water increases, and the fluidity continues to improve. After exceeding 60%, the fluidity deteriorates, and the high content leads to an increase in the porosity of the aggregate, requiring more slurry to coat it. The setting time decreases with the increase of the coarse aggregate content of steel slag. With the increase of the steel slag content, the overall alkalinity of the slurry decreases significantly (due to the superposition of the "alkaline dilution effect" of multi-particle steel slag), and the catalytic effect on cement hydration continues to weaken.

[0227] Data from Example 1 and Comparative Examples 6-8 show that as the content of fine aggregate made from carbide steel slag increases (≤40%), the initial slump and spread of the concrete mixture decrease, and the fluidity decreases significantly after exceeding 40%. The reason is the same as that for coarse aggregate made from carbide steel slag.

[0228] Observations of Example 1 and Comparative Examples 5, 9, and 10 also revealed that the concrete with steel slag aggregate after carbonation treatment had significantly better fluidity than that without carbonation treatment, and the setting time was delayed by about 30 to 36 minutes. This is because the products such as CaCO3 generated by the carbonation reaction fill some of the pores on the surface and inside of the steel slag aggregate. Although carbonation will form a porous structure on the surface of the aggregate, the filling effect of the products can reduce the effective water absorption rate of the aggregate and reduce its additional consumption of mixing water, thereby offsetting the negative impact of the increased water absorption rate caused by carbonation on fluidity.

[0229] As can be seen from Example 1 and Comparative Example 11, the fluidity of concrete with modified decommissioned wind turbine blade glass fiber is slightly lower than that without modified decommissioned wind turbine blade glass fiber. However, as can be seen from Comparative Example 12, the modified glass fiber can improve the fluidity of the concrete mixture.

[0230] Compared to Example 1, Comparative Example 13 shows that the overall workability of concrete made with carbonized steel slag powder is better than that made with uncarbonized steel slag powder.

[0231] Table 2. Drying shrinkage rates of concrete obtained in Examples 1 and Comparative Examples 1-13

[0232]

[0233] Table 3. Crack resistance coefficients of concrete prepared in Examples 1-4 and Comparative Examples 1-13

[0234]

[0235] From the shrinkage rate and cracking performance data in Tables 2 and 3:

[0236] The concrete performance in Examples 1-4 was generally similar: Regarding drying shrinkage, from 1 to 28 days of age, the values ​​for each age group in the four examples remained within a similar range with minimal fluctuations; in terms of cracking performance, the initial cracking time was concentrated between 154 and 163 minutes, and the maximum crack width remained stable between 0.121 and 0.131 mm. Other cracking-related indicators (such as...) a c , u unit The numerical differences in the values ​​of (etc.) are not significant, indicating that the drying shrinkage rate and cracking performance of these four groups of concrete all show strong consistency.

[0237] As shown in Tables 2 and 3, Examples 1 and Comparative Examples 1-13 show that as the content of coarse aggregate of steel slag increases (0-60%), the shrinkage rate and the maximum crack width are optimal when the content of coarse aggregate of steel slag is 60%, the content of coarse aggregate of steel slag is 40%, and the content of glass fiber in the modified decommissioned wind turbine blade is 3 parts.

[0238] Compared with Example 1 and Comparative Examples 5, 9, and 10, carbonized steel slag aggregate significantly improved drying shrinkage and crack resistance. This is because uncarbonized steel slag aggregate contains more active components and pores, making it prone to volume changes under hydration, hardening, and environmental influences. Furthermore, its relatively weak interfacial transition zone makes it more susceptible to drying shrinkage cracks. In contrast, the volume stability of carbonized products is superior to that of uncarbonized steel slag, reducing the aggregate's own volume deformation and thus inhibiting the accumulation of shrinkage stress within the concrete. The optimal drying shrinkage performance was observed when the coarse aggregate content of carbonized steel slag was 60%, the fine aggregate content was 40%, and the modified decommissioned wind turbine blade glass fiber content was 1.25%.

[0239] As can be seen from the data in Table 3, the drying shrinkage rate of Example 1 (corresponding to the same dosage combination) is much lower than that of most comparative examples, especially the groups with unoptimized dosage or low dosage of carbonized steel slag aggregate. Furthermore, the drying shrinkage rate of Example 1 stabilized and showed a slight decrease after the mid-curing period, demonstrating excellent volume stability. From Example 1 and Comparative Example 11, it is evident that concrete incorporating modified decommissioned wind turbine blade glass fiber exhibits better cracking and drying shrinkage performance than the group without it. This is because the "bridging effect" of the decommissioned wind turbine blade glass fiber disperses stress and delays crack initiation, acting like adding "elastic reinforcement" to the concrete, constraining the development of microcracks and postponing initial cracking. The uniform distribution of glass fiber forms a network, reducing stress concentration points and inhibiting the random generation of numerous microcracks. Without glass fiber, the matrix has more defects and is prone to multiple cracks, or excessive glass fiber content in the decommissioned wind turbine blades can easily lead to agglomeration, promoting cracking. On the other hand, glass fiber reduces the total cracked area through the "crack-resistant triangle" (delaying cracking, limiting crack width, and reducing the number of cracks).

[0240] As shown in Example 1 and Comparative Example 12, the cracking and drying shrinkage properties of the modified glass fiber concrete for decommissioned wind turbine blades are significantly better than those of the unmodified similar fiber concrete. Furthermore, compared to Example 1, Comparative Example 13 indicates that the shrinkage and cracking properties of the concrete made with carbonized steel slag powder are superior to those of the uncarbonized steel slag powder.

[0241] Table 4. Compressive strength and mass loss rate of concrete prepared in Examples 1-4 and Comparative Examples 1-13 before and after high temperature.

[0242]

[0243] As can be seen from the data in Table 4, the compressive strength and mass loss rate of concrete in Examples 1 to 4 are quite similar: from 25℃ to 800℃, the compressive strength values ​​of the four examples are always in a similar range. For example, at 25℃, they are concentrated between 66 and 70 MPa, and at 800℃, they are also in the range of 51 to 56 MPa, with very small fluctuations.

[0244] Meanwhile, as shown in Table 4, the four embodiments exhibited good residual compressive strength at room temperature and after exposure to high temperatures ranging from 200 to 800°C. At 800°C, the strength loss rate and mass loss rate were only 18.2% and 4.32%, respectively, significantly lower than all comparative examples. This is because: ① Glass fiber still retains a certain tensile strength at high temperatures, and the "bridging" cracks inhibit propagation, reducing the sharp drop in strength caused by crack penetration; without glass fiber, matrix cracking is more severe, resulting in greater strength loss. Glass fiber enhances the matrix's density and reduces internal porosity, while evaporation of pore water is the main cause of mass loss. ② Steel slag contains iron phases, MgO, etc., and has an extremely high melting point. Its volume stability at high temperatures is superior to ordinary aggregates (ordinary aggregates are prone to cracking due to uneven thermal expansion); furthermore, the steel slag undergoes carbonization treatment, resulting in strong interfacial bonding and better aggregate-matrix synergistic stress distribution at high temperatures. ③ The three-dimensional network structure formed by the alkali activator, slag powder, fly ash, and carbide steel slag powder endows it with good low thermal conductivity. Furthermore, it promotes the formation of zeolite-like phases in slag powder and fly ash, making it more stable at high temperatures (common hydration products such as Ca(OH)2 decompose at around 400℃, resulting in a sharp drop in strength). In addition, compared to Example 1, the results of Comparative Example 13 show that carbide steel slag powder has a better effect on improving the strength performance and quality retention rate of concrete than uncarbide steel slag powder.

[0245] Table 5 Radiation shielding efficiency of concrete obtained in Examples 1-4 and Comparative Examples 1-13

[0246]

[0247] As can be seen from the radiation protection efficiency data in Table 5, the concrete in Examples 1-4 exhibits relatively similar performance: the apparent density is concentrated in the range of 3.62-3.65 g / cm³, indicating good radiation protection efficiency. 60 The linear absorption coefficient of Co γ rays is in the range of 0.3431-0.3523 cm⁻¹. -1 The half-life thickness remained stable within the range of 1.35-1.41 cm, and the differences in the values ​​of various indicators were relatively small, indicating that the radiation protection efficiency of these four groups of concrete was generally consistent.

[0248] In addition, Table 5 contains... 60The absorption efficiency and linear absorption coefficient of Co gamma rays are the core evaluation indicators of radiation protection performance (the higher the absorption efficiency and the larger the linear absorption coefficient, the stronger the radiation protection capability). Half-life thickness is a derived indicator (the smaller the value, the faster the ray attenuation rate, and the better the radiation protection effect). Apparent density mainly reflects the material density and the content of heavy elements (such as Fe and Ca in steel slag), and is positively correlated with radiation protection performance. The replacement rate of carbide steel slag aggregate has a non-linear effect on radiation protection performance. When the replacement rate of coarse carbide steel slag aggregate increases from 0% to 60%, the absorption efficiency increases from 0.1562 to 0.3523, and decreases to 0.2986 at a 80% replacement rate due to increased porosity caused by gradation imbalance. When the replacement rate of fine carbide steel slag aggregate increases from 0% to 40%, the absorption efficiency increases from 0.3087 to 0.3523, and slightly decreases to 0.3468 at a 60% replacement rate. Excessively high replacement rates affect the slurry encapsulation due to increased specific surface area.

[0249] The absorption efficiency of uncarbonized aggregate samples (Comparative Examples 5, 9, and 10) was 10.2%–24.8% lower than that of Example 1. Carbonization treatment enhanced radiation protection by increasing density and activating active components. Among the three, Comparative Example 10 had the worst radiation protection. The modification and dosage of glass fiber in retired wind turbine blades were key control factors. The absorption efficiency of the sample without glass fiber (Comparative Example 11) was 10.7% lower than that of Example 1, and the absorption efficiency of the unmodified glass fiber sample (Comparative Example 12) was 15.5% lower. Modification treatment improved interfacial compatibility through etching roughening and silane coupling.

[0250] Furthermore, compared with Example 1, the results of Comparative Example 13 show that carbonized steel slag powder has a better effect on improving the radiation protection performance of concrete than uncarbonized steel slag powder.

[0251] In summary, the optimization principle for radiation protection performance is as follows: the ratio of coarse aggregate to fine aggregate of carbonized steel slag maximizes density; aggregate carbonization treatment enhances the enrichment and activation of heavy elements; and modified glass fiber strengthens the suppression of internal defects through interface reflection. The three work together to form a radiation protection system of "dense structure - heavy element absorption - interface enhancement", which takes into account both performance and the advantages of solid waste resource utilization.

[0252] In summary, the solid waste steel slag of this invention, after carbonization treatment, and the decommissioned wind turbine blade glass fiber after chemical modification, combined with alkali-activated geopolymer cementitious materials, can prepare alkali-activated zero-cement all-solid-waste heat-resistant and radiation-resistant concrete based on decommissioned wind turbine blade glass fiber reinforcement. This concrete has good workability, strength, low drying shrinkage and cracking, and superior radiation protection performance, and can be effectively applied to heat-resistant and high-radiation concrete engineering scenarios at 200~800℃.

[0253] The above description of the embodiments is provided to enable those skilled in the art to understand and use the present invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A type of alkali-activated zero-cement solid waste heat-resistant concrete based on glass fiber reinforced decommissioned wind turbine blades, characterized in that, The components include the following parts by weight: 63-80 parts of slag powder 25-35 parts fly ash 5-20 parts of carbide steel slag powder 92-136 parts natural coarse aggregate, 138-204 parts of coarse aggregate made from carbide steel slag. River sand 96-135 parts, 64-90 parts of fine aggregate from carbide steel slag. 45-60 parts water 5-10 parts of alkali activator Modified decommissioned wind turbine blades, 1-3 parts fiberglass, Water-reducing agent 0.5-3 parts, 0.5-3 parts of retarder; The modified decommissioned wind turbine blade fiber is obtained by cutting, crushing, milling, and screening decommissioned wind turbine blades in sequence, and then modifying them with NaOH solution and aminopropyltriethoxysilane solution, with a length of 6~12mm. The carbide steel slag powder, coarse aggregate, and fine aggregate are all obtained from raw steel slag ore through crushing, screening, and carbonization. The specific preparation methods are as follows: (1) Using steel slag ore as raw material, the ore is crushed by a jaw crusher and then graded and screened. While removing impurities, the undersize material with a particle size of less than 4.75 mm is retained as raw material for fine aggregate of carbide steel slag and powder of carbide steel slag. (2) In step (1), steel slag coarse aggregate with a sieve residue size between 4.75 and 20 mm is obtained by grading and screening. It is then subjected to high-pressure water washing, pre-wetting mixing and homogenization, and carbonization treatment. Finally, carbonization product debris is removed by secondary screening to obtain standardized carbonized steel slag coarse aggregate with a specific surface area of ​​150 to 750 m² / kg and a density of 3.1 to 3.8 g / cm³. In step (2), the moisture content of the steel slag coarse aggregate is controlled to be 10-15% through pre-wetting, mixing, and homogenization. (3) Using the undersize material in step (1) as the basic raw material, after crushing and grinding, the undersize material with a particle size of less than 0.075 mm is retained as the raw material for preparing carbide steel slag powder. The remaining particles with a particle size range of 0.075~4.75 mm are dried, dehydrated, carbonized, cooled and screened to obtain fine aggregate of carbide steel slag with a specific surface area of ​​200~600 m² / kg and a particle size range of 0.075~4.75 mm. (4) Using the undersize material with a particle size of less than 0.075 mm in step (3) as the core raw material, after drying and dehumidifying, deep grinding to increase the specific surface area, and then carbonization treatment and graded purification, the carbonized steel slag powder material with a particle size of <0.075 mm is finally obtained.

2. The alkali-activated zero-cement solid waste heat-resistant concrete according to claim 1, characterized in that, In the preparation method of the carbonized steel slag powder, carbonized steel slag coarse aggregate and carbonized steel slag fine aggregate, the carbonization treatment in step (2) is as follows: steel slag coarse aggregate with a particle size between 4.75 and 20 mm is evenly spread in a sealed blower carbonization silo, and the thickness of the material layer is controlled at 10 to 20 cm to ensure CO2 diffusion efficiency. A CO2 / air mixture with a CO2 volume concentration of 20% to 50% is introduced to carry out the carbonization reaction. The humidification and blower systems are turned on simultaneously to maintain the temperature inside the silo at 20 to 30°C and the relative humidity at 70% to 90%. The carbonization reaction lasts for 12 to 72 hours. During this period, the material is turned over 2 to 3 times by the turning system. The reaction is terminated when the pH of the steel slag coarse aggregate surface drops to 8 to 9. After discharge, the material is transferred to the drying silo by a belt conveyor and treated with natural air drying or a low temperature drying process at ≤60°C until the moisture content is ≤1%. The drying temperature in step (3) is 80℃, and the moisture content of the dried material needs to be reduced to ≤1%. The carbonization treatment method described in step (3) is the same as the carbonization treatment method for steel slag coarse aggregate in step (2); The drying temperature in step (4) is 40~60℃, and the sieve material is dried to a moisture content of ≤0.5%; the specific surface area after deep grinding is 350~850m² / kg; In step (4), an air classifier is used for classification and purification. The specific operation is as follows: adjust the speed of the classifier wheel to 2500~4000 r / min, control the negative pressure to -5~-10 kPa, separate the coarse particles with a particle size >0.075mm, return them to the furnace for secondary grinding, and collect the carbide steel slag powder material with a particle size <0.075mm. The carbonization process described in step (4) is slurry carbonization: ultrafine steel slag powder dried to a moisture content of ≤0.5% is prepared into a slurry with a solid content of 30%~40%. After stirring at a high speed of not less than 100r / min for 10~15min, it is transferred to a high-pressure reactor. Pure CO2 is introduced to increase the pressure to 0.2~0.3 MPa and the temperature to 30~40℃. Microbubble aeration reaction is carried out for 2~6h. The reaction is terminated when the pH of the slurry stabilizes at 7.0~7.

5. After plate and frame filtration, drying at 50~60℃ to constant weight and cooling and sieving, carbonized steel slag powder is obtained.

3. The alkali-activated zero-cement solid waste heat-resistant concrete according to claim 1, characterized in that, The slag powder is S95 grade granulated blast furnace slag powder, with a particle size range of 0.5~45μm and a specific surface area of ​​400~500m². 2 / kg; The fly ash is Class F, Grade II fly ash, with a particle size range of 1~10μm and a specific surface area of ​​250~300m². 2 / kg; The natural coarse aggregate has a particle size of 4.75~20mm, and the fineness modulus of the river sand is 2.5~3.

4. The alkali-activated zero-cement solid waste heat-resistant concrete according to claim 1, characterized in that, The alkaline activator is a mixed aqueous solution of water glass and sodium hydroxide; The sodium hydroxide has a purity of over 99% and is a white powdery solid. The water glass is sodium metasilicate nonahydrate, with a Na2O content of 8.74% and a SiO2 content of 27.64%.

5. The alkali-activated zero-cement solid waste heat-resistant concrete according to claim 4, characterized in that, The preparation method of the alkali activator includes: preparing a sodium hydroxide solution by mixing sodium hydroxide and water at a mass ratio of 1:1, stirring evenly, and then letting it stand for 12 to 24 hours in an environment with a temperature of 20 to 25°C and a humidity of 60 to 70%. Before the actual use of the alkali activator, the sodium hydroxide solution is mixed and stirred evenly with water glass to obtain an alkali activator with a target modulus of 1.0 to 1.

8.

6. The alkali-activated zero-cement solid waste heat-resistant concrete according to claim 1, characterized in that, The specific steps of the preparation method for the modified decommissioned wind turbine blade fiber are as follows: ① Use a cutting machine to cut large retired wind turbine blades into small block materials of 50~100mm. Use a jaw crusher combined with an impact crusher to mechanically crush the cut materials to form granular or flaky structures of 5~15mm. ② High-pressure water washing is used to initially remove contaminants from the blade surface. Then, a combination of physical methods, including mechanical grinding, high-speed stirring, airflow separation, and vibrating sieving, is used to break down the resin matrix using shear force, gradually separating out recycled glass fibers with a length controllable between 6 and 12 mm. ③ Weigh out analytical grade NaOH and dissolve it in deionized water to prepare an alkaline treatment solution with a concentration of 2~4 mol / L; immerse the recycled glass fiber in the alkaline treatment solution at a solid-liquid ratio of 1:20~30, control the treatment temperature at 80~95℃, and soak for 10~20 minutes to achieve degumming and activation of the fiber surface; ④ After draining the fibers, rinse them in a 0.5~1mol / L HCl solution for 8~15 minutes to remove residual NaOH and impurities from the fiber surface. Then rinse them with deionized water 3~5 times and place them in a forced-air drying oven at 60~80℃ for 0.5~1.5 hours until the fiber moisture content is ≤0.5%. ⑤ Prepare an aminopropyltriethoxysilane solution using aminopropyltriethoxysilane and deionized water at a volume ratio of 1:99, and let the prepared aqueous solution stand for 24 hours; immerse the fiber obtained in step ④ in the aminopropyltriethoxysilane solution for 15 minutes, remove it and drain off the excess solution on the surface to obtain the modified decommissioned wind turbine blade glass fiber.

7. The alkali-activated zero-cement solid waste heat-resistant concrete according to claim 6, characterized in that, The water pressure for high-pressure water washing in step ② is 0.8~1.2MPa; The grinding speed is 300~500 r / min; the high-speed stirring speed is 800~1200 r / min; the air velocity during air separation is 10~15 m / s; and the screen aperture used in vibrating screening is 6~12 mm.

8. The alkali-activated zero-cement solid waste heat-resistant concrete according to claim 1, characterized in that, The water-reducing agent is selected from any one or a mixture of more than one of naphthalene-based high-efficiency water-reducing agents, modified polycarboxylate water-reducing agents, and melamine-formaldehyde condensates. The retarder is selected from any one or a mixture of one or more of sucrose, calcium lignosulfonate, citric acid, malic acid, and barium chloride.

9. A method for preparing alkali-activated zero-cement solid waste heat-resistant concrete according to any one of claims 1 to 8, characterized in that, Includes the following steps: (1) Weigh all materials according to the mix proportion and store them in a dry container. Prepare the alkali activator solution according to the measurement 30 minutes before pouring the concrete specimen. At the same time, add the water-reducing agent and retarder into the mixing water to make a water-water mixture. Stir until completely dissolved, seal and let stand for later use. (2) Pour natural coarse aggregate, coarse aggregate of carbide steel slag, river sand, fine aggregate of carbide steel slag, 1 / 2 part by weight of slag powder, 1 / 2 part by weight of fly ash, and 1 / 2 part by weight of carbide steel slag powder into a mixer. After premixing at a speed of 60~80 r / min for 30 seconds, add modified decommissioned wind turbine blade glass fiber evenly while mixing, and continue mixing at 60~80 r / min for 0.5 min. (3) Take 60%~70% of the weight of the water mixture from step (1), and slowly pour it into the mixer along with the alkali activator solution, and stir at 120~150 r / min for 1 min; (4) Add the remaining 1 / 2 part by weight of fly ash, 1 / 2 part by weight of slag powder and 1 / 2 part by weight of carbide steel slag powder to the mixer, and stir at a speed of 120~150 r / min for 1 min; (5) Pour the remaining 30%~40% by weight of water mixture from step (1) into the product stirred in step (4), and continue stirring at 120~150 r / min for 1 min. After discharging and testing the workability, cast the specimen. (6) The concrete is poured into the mold, vibrated, and left to stand at room temperature for 24 hours before being demolded. Then it is placed in a standard curing box and cured for the specified age to obtain the alkali-activated zero cement solid waste heat-resistant concrete.

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